Ekktbst mitchell



Aug. 28, 1928.

' E. MITCH ELL Filed Aug. 8,

Patented Aug. 28, 1928.

UNITED STATES PATENT OFFICE.

Application filed August 8, mat Serial No. 211,546, and in Great Britain October 14,1928.

structure to the metal of the propeller with the fibres running approximately parallel with the' exterior surface of'thc propeller blades.

My invention comprises the production of separate propeller blades by extruding the metal in a direction parallel with the length of the blade into and through a die which greatly reduces the cross sectional area and alters the shape of the metal until it issues into the atmosphere. 7 I

Referring to the accompanying sheet of ex lanatory drawings igure 1 is a sectional elevation representing a container and die for the production of propeller blades in accordance with this invention.

, Figures 2 to 7 inclusive are sectional plans taken on the respective lines 2 to 7 in Figure 1. The metal to be extruded which ma be in the form of a round ingot at a suitab e temperature, is placed in the container a and has pressure applied thereto by hydraulic means in the direction indicated by the arrows at Figure 1, whereby it is forced or extruded through the die I) shaped to conform with the root and part of the length of the propeller blade to be produced. f The interior conformation of the combined container and die varies in the manner indicated by the sectional plan views at Figures 2 to 7, said views being taken on the corresponding lines 2 to 7 of Flgure 1.

A part of the metal issues from said die into the open, the die, for example, enclosing one half or one third the length of the pro- 40 Keller blade. The complete blade is finished y machmery.

A container and die are in line'with the blade being produced; the metal thus flows in a direction generally parallel with the pro- 4 peller exterior.

Iii the illustrated example, the container and die are combined; they may, 'however,'be separate parts and adapted to be united in tandem or end to end. In either case, they are made in halves or segments to permit of lateral withdrawal from the extruded propeller.

What I claim is:

In the manufacture of a propeller blade,

a die shaped to correspond with the cross section and twist of the root and a portion only of the length of the blade, the end of said die being open so that the metal issues into the atmosphere from the die, a container for the metal in alignment with the die which con- 50 stitutes a continuation of the container, and means extruding the metal from "said container into said die and partly into the atmosphere through the die.

In testimony whereof I have signed my name to this specification.

ERNEST MITCHELL. 

